Silica encapsulation of ureolytic bacteria for self-healing of cement-based composites

Patent metadata

Field	Value
Publication number	US-2018072632-A1
Application number	US-201715703682-A
Country	US
Kind code	A1
Filing date	Sep 13, 2017
Priority date	Sep 14, 2016
Publication date	Mar 15, 2018
Grant date	—

Abstract

One aspect of the present invention is directed to a method of preparing encapsulated ureolytic cells. This method includes blending freeze dried ureolytic cells and an aqueous solution to form a base mixture; mixing the base mixture with a silicate-forming compound to form a blend comprising silica encapsulated ureolytic cells; and freeze drying the silica encapsulated ureolytic cells. The present invention also relates to a method of producing a self-healing concrete. This method comprises providing silica encapsulated freeze-dried ureolytic cells; mixing the silica encapsulated freeze-dried ureolytic cells with cement to form a mixture; and blending the mixture with a calcium salt and a urea solution to form a concrete mixture. Also disclosed are silica encapsulated ureolytic cells, a method of making a concrete form, and a cured concrete product.

First claim

What is claimed:

1 . A method of preparing encapsulated ureolytic cells, said method comprising:
blending freeze dried ureolytic cells and an aqueous solution to form a base mixture; mixing the base mixture with a silicate-forming compound to form a blend comprising silica encapsulated ureolytic cells; and freeze drying the silica encapsulated ureolytic cells.

2 . The method of claim 1 , wherein the solution contains a base precursor.

3 . The method of claim 2 , wherein the base precursor is urea.

4 . The method of claim 1 , wherein the ureolytic cells are selected from the group consisting of Sporosacina pateurii, Sporsacina ureae, Bacillus sphaericus, Bacillus pseudofirmus, Bacillus cohnii , and Bacillus alkalinitrilicus.

5 . The method of claim 1 , wherein the silicate-forming compound is an organosilicate compound.

6 . The method of claim 5 , wherein the organosilicate compound is selected from the group consisting of tetraethyl orthosilicate, tetramethyl orthosilicate, tetraprophy orthosilicate, and tetrabutyl orthosilicate.

7 . The method of claim 1 further comprising:
washing the mixture and
recovering the encapsulated cells prior to said freeze drying.

8 . The method of claim 7 , wherein said recovering is carried out by precipitation or centrifugation.

9 . The method of claim 1 , wherein said blending is carried out at a temperature of 0 to 100° C.

10 . The method of claim 1 , wherein said mixing is carried out at a temperature of 20 to 50° C.

11 . The silica encapsulated ureolytic cells produced by the method of claim 1 .

12 . Freeze-dried ureolytic cells encapsulated with silica.

13 . The freeze-dried ureolytic cells of claim 12 , wherein the cells are selected from the group consisting of Sporosacina pateurii, Sporsacina ureae, Bacillus sphaericus, Bacillus pseudofirmus, Bacillus cohnii , and Bacillus alkalinitrilicus.

14 . A method of producing a self-healing concrete comprising:
providing silica encapsulated freeze-dried ureolytic cells; mixing the silica encapsulated freeze-dried ureolytic cells with cement to form a mixture; and blending the mixture with a calcium salt and a urea solution to form a concrete mixture.

15 . The method of claim 14 , wherein the ureolytic cells are selected from the group consisting of Sporosacina pateurii, Sporsacina ureae, Bacillus sphaericus, Bacillus pseudofirmus, Bacillus cohnii , and Bacillus alkalinitrilicus.

16 . The method of claim 14 , wherein the calcium salt is selected from the group consisting of calcium chloride, calcium acetate, calcium bromide, calcium lactate, calcium citrate, calcium nitrate, and calcium gluconate.

17 . The method of claim 14 , wherein said mixing is carried out at 10 to 32° C.

18 . The method of claim 14 , wherein said blending is carried out at 10 to 32° C.

19 . The concrete product produced by the method of claim 14 .

20 . A concrete product mixture comprising:
freeze-dried ureolytic cells encapsulated with silica; concrete; urea solution; and calcium salt.

21 . The concrete product of claim 20 , wherein the ureolytic cells are selected from the group consisting of Sporosacina pateurii, Sporsacina ureae, Bacillus sphaericus, Bacillus pseudofirmus, Bacillus cohnii , and Bacillus alkalinitrilicus.

22 . The concrete product of claim 20 , wherein the calcium salt is selected from the group consisting of calcium chloride, calcium acetate, calcium bromide, calcium lactate, calcium citrate, calcium nitrate, and calcium gluconate.

23 . A method of making a concrete form comprising:
forming the concrete product of claim 20 into a desired shape and curing the formed concrete.

24 . The method of claim 23 , wherein the ureolytic cells are selected from the group consisting of Sporosacina pateurii, Sporsacina ureae, Bacillus sphaericus, Bacillus pseudofirmus, Bacillus cohnii , and Bacillus alkalinitrilicus.

25 . The method of claim 23 , wherein said forming is carried out at 10 to 32° C.

26 . The method of claim 23 , wherein said curing is carried out at 16 to 27° C.

27 . The cured concrete product of claim 23 .

Assignees

• Univ Iowa State Res Found Inc

Inventors

• Wang Kejin
• Huang Wenyu
• LOMBOY Gilson
• Pei Yuchen
• Qi Zhiyuan

Classifications

• C12N11/14

  Enzymes or microbial cells immobilised on or in an inorganic carrier · CPC title

• C04B40/0675

  Mortars activated by rain, percolating or sucked-up water; Self-healing mortars or concrete · CPC title

• C04B24/126

  Urea · CPC title

• C04B22/124

  Chlorides of ammonium or of the alkali or alkaline earth metals, e.g. calcium chloride · CPC title

• C04B28/04

  Portland cements · CPC title